Method and apparatus fob manufac



Aug. 7, 1951 R. COLOMBO 2,563,396

METHOD AND APPARATUS ROR MANUFACTURING EY EXTRUSION STRUCTURAL MEMBERS FROM THERMOPLASTIC SYNTHETIC RESINS Filed Aug. 7, 1947 2 Sheets-Sheet 1 HOI a A HOA @Rw/AWV@ Aug. 7, 1951 4 COLQMBO 2,563,396

METHOD AND ARATUS MANUFACTURING BY EXTRUSION STRUCTU MEMBERS FROM THERMOPLSTIC SYNTHETIC RESINS Filed ug. 7, 1947 2 Sheets-Sheet 2 FIGB FIG] Y Y q Q' f ,j 7 z w//enfor ganzi;

Patented Aug. 7, 1,951

assault` METHoD AND APPARTUS FOR MANUFAC- TURING BY EXTRUsIoN STRUCTURAL MEMBERS FRoM THERMOPLASTIC SYN- THETIC RE SIN S Roberto Colombo, Turinfrltaly, assignor toliiguna n* S. A., Zurichf Switzerland Application August 7, 1947, Serial No. 766,912

In FranceFebruary 2, 1940 Section 1, Public Law 690, August 8, 1946 Patent expires February 2, 196i) 4 Claims.

This invention relates to screw presses emrosities.

According to this invention I employ at least two intermeshing screws rotating in the same direction and such as to effect, besides mixing of the material, an increment in pressure.

In a rst construction of the object of my invention, this is `obtained by making the screws of gradually decreasing diameter, the section of larger diameter being of course on the feed side.

In order to further increase the compression of the material inthe space between the threads of both screws, the various sections may be of different pitch, so that if in the first section there is for example 1 turn `per inch, in the second section there will be V11/ `turns per inch and so on, thus obtaining a gradually increasing compression. Generally, the material remains in the screw casing only the strictly necessary time for its advancement along the screw threads, such time being so controlled that the material reaches a fully molten state. vIn some cases it may be necessary for the material to undergo, after melting, aprolonged bakinginside the casing. In 'this case a chamber of a certain volume is provided in the casing; the material advances slowly in said chamber `and is thus submitted essary baking. I A

The` annexed drawing shows, byway of example, some embodiments of the apparatus according to this invention. A -i Figuressl and 2 are a cross section and a plan view respectively of an apparatus in its simplest form constituted by two interengaging screws.

Figure 3 is a part longitudinal section of the interengaging screws.`

Figures 4 and 5 are a cross section anda plan View respectively of an arrangement comprising ff six scr-ews placed side by side and having interengaging threads, suitable for the manufacture oi sheets or structural members of considerable width.

Figure 6 shows an embodiment, in which the engaging screws are circularly arranged.Y `This construction is more particularly adapted for the manufacture of tubes of large diameter.

Figures 7 and 8 show improved constructions adapted for particular cases.

Referring tothev drawing, I is the body of the apparatus having a recess invwhich are located,`

as shown in Fig. l, two screws 2, 3 with parallel axes and interengaging threads 2', 3. The screws are rotated in the same sense each by means of to the necfA a separate'driving ployed in the manufacture by extrusion of arti- I 2 mechanism not shown for clearness sake.

The material is filled into the space 2",-3` (Fig. 3)r between the threads through the feed openings 4 and `is advanced along each screw, owing to the fact that the thread of the other screw closes said space witha suilicient tight llt-'i ting to prevent the material from turning with the screw. The thread of one of the screws serves to stop advancement lof'the'material iillingthe clearance between the threads of the other screw; Itwill be easily understoodthat, when starting from material of high speciiic volume, the screw threads would not always be filled with material thus reducing eiiiciency. It is therefore necessary to use screw Sections I3 and I4 (Fig. 7) hav` ing Vthreads of different diameter and, if necessary, also of diierent pitch, so that the material is admitted to the iirst `section of larger diameter and higher pitchat a higher specific volume k and fed into the second section in a slightly compressed state and so on in the following sections at gradually increased pressure.

The material is thus forced to advance under high pressure and, as it has been ascertained in the practice, a thorough mixing of the material is obtained.` The material is pressed from the space at the screwend by the newly fed material towards the die opening iwhich may for instance beof the vshape shown in Figure 2. In the modified form shown lin Figures 4 and 5, a set of screws T- 6 fis mounted'in* the casing 1 having f-eed openings 8 for each screw 6. 9 denotes the die opening, which may be-of elongated form for producing a sheet as shown in the drawing.

In the modified construction shownin Figure "l 6, the screws ID, insteadof-being arranged in a row, as shown in Fig.4`, are arranged on a closed` ring in a casing Il provided with an opening i 2 for each screw.

`In this construction the-drawing die opening may be formed in a surfaceperpendicular to the screw axis, for instance in the form of an annular slot for producing tubes of ordinary and larger diameter, while tubesroi smaller diameter may also. be producedon the apparatus shown in Figi uresl and 2.

According to ythe invention, the smooth and compact material issuing'in ahig'hly compressed state from the drawing die may beled by means of suitably shaped surfaces arranged in proximity to the die opening insuch manner'as to Wind the drawn material onl a plane. for instance in spiral form or in space, `for instance inl helical form.

sible t'-; ;pbta Y, l stru 1; member for; thermoplastic lm eri .s'fwhichi guided? by suit@ able templates while in the soft state may be d1- rected along a helical path. The blank may bevvv 'ii' transformed on a suitalolel man11135.11,Jntoahose-v lr of thermoplastic material,th ber being spirally wound w in a single continuous oper ,Lslsi'fiisssrisws irtssid 001i 'i 'in isaldffoutlctopening. 2. An apparatus for manufacturing by extrusion structural members from thermoplastic syntlietn;L resins-,comprising intermeshing screws hav 'gf Valll-ax all arranged to rotate in the f saineld ectioninwhich the thread of each screw feeding the thermoplastic material and y,ending with the winding of the strutttiall@memAJ ing from the drawing die in the spiral fo' producing a hose.

The apparatus according to the invention also be used for manufacturingstructuralYmemf bers of heat hardened materials. Thejmafteria fed through the feed opening is admitted unde pressure into the casing at room temperature Jom if necessary, is cooled ang passes into the drawine diawhichmarbs Qi axsutabls,foljrnfheated t`o"su'h"aI temperaturfthat the mater-i( melts and then is 1hardened to awell. defined formoorrsseondinsis d'isLfQ' t` hardening material itispos-v lslls-.Lths s fiswgplpulsion es esstrssfinlts be uses sta hier; 'pressure `i threaded sessies," tigri.' Ale lgfj large di ,ma rial treatsslwith hat, sus coavisnient solvents although. 1t 9s esn the, rst step ,o-.thsmethod according. to` this invention. Ya petten-mora Ycori-spam r ,and iin: ishsd materiel; isfaltsadysbtained.tremathsldraweing die'tlus reducing the cost of manu facture:,-,

` ention 1,-; An apparatus.. ,for manufacturing f 'bymex-.f r l trasloni stitlatuelimsmbsrs framethema Oplastic synthetic resinsn comprising intermeshingscrews,

y h thathread cfpeach `#Spacesbetween@the 1 A fanti lower.; ptshfi L Same, a

COmDlejtely llsf;the spaces between the threads of, thescrewsV orA 4screws intermeshing with the l "ntainerc'orlning said screws and fitting the'outer perimeters thereof, means for .driyinglsaidtscrews the threads of said screws f having. a decreasing pitch and diameter from said inleuto saidmoutlet opening, each screw compris- 5tingen;intermediate non-screwed section, on

" 'w Ich s tion the container is of the same outlineiason the preceding screwed section, the container being sharply reiuced after the smooth session te, thssmsllsa diameter the. successive 3'. An apparatus for manufacturing b ,-ex-, ifuspilastrusmrsl msmbsrs ,.fremthstrmoplasti@ systhstis rssins comprising a plurality. @fristen msshmgrrsw; havingfeslellel @XSS lying the. same plane,L rrI-iL-,all:arranged-torotatefin the ssms-diretisnin which e--thssadoffeashscrsw semplsisly llsthsspsse tween the threads@ the screw ,srfsfsws t sshinefwiikl the same', a @Qntsinsr ,confining sldlssrsws ardfttins-ihe screw -ftha threads-tof-saidsersws haring. ,s-,de-A. frmfssld'inlstto .if nemesi nlstfepniessfio, said 'screws Container! snfsutlst-:Ossnirisi-,frsmesaidf seres/Sfmtsaitilsntanes. and@ forming fdis.- fin 'd Y Y turisefflby eX:Y gehsrmslsstici :plu-ral'itrfeintsrw .elfaxsslying Ona 11 rranesd Atogrstate in;

if, to' said screws in'said containegkzari utletopenf oBERroecoLoMBo;

Theffollowingf references are offirecord -inv the lll 562996 1,@31317 

1. AN APPARATUS FOR MANUFATURING BY EXTRUSION STRUCTURAL MEMBERS FROM THERMOPLASTIC SYNTHETIC RESINS COMPRISING INTERMESHING SCREWS HAVING PARALLEL AXES ALL ARRANGED TO ROTATE IN THE SAME DIRECTION IN WHICH THE THREAD OF EACH SCREW COMPLETELY FILLS THE SPACES BETWEEN THE THREADS OF THE SCREW OR SCREWS INTERMESHING WITH THE SAME, A CONTAINER CONFINING SAID SCREWS AND FITTING THE OUTER PERIMETERS THEREOF, MEANS FOR DRIVING SAID SCREWS, THE THREADS OF SAID SCREWS HAVING A DECREASING PITCH AND DIAMETER FROM SAID INLET TO SAID OUTLET OPENING, INLET OPENINGS TO SAID SCREWS IN SAID CONTAINER, AND OUTLET OPENING FROM SAID SCREWS IN SAID CONTAINER, AND A FORMING DIE IN SAID OUTLET OPENING. 